From: Milton Aupperle <milton@outcastsoft.com>
Date: October 1, 2005 12:04:52 PM MDT
To: Astro_IIDC@yahoogroups.com
Subject: Re: [Astro_IIDC] Planning on a better camera
Hi Alan;
On 1-Oct-05, at 11:02 AM, Alan Friedman wrote:
Hi Duane -
Sorry - meant to respond to your post yesterday.
For planetary imaging, the smaller chip is best. The planets will fit on the small chip nicely even at f50. Beyond this is probably useless oversampling. The bigger chip would be nice for lunar imaging at high resolution. But here you have a lot of light so the faster download rate of the smaller chip will be helpful too as you battle the seeing. And you can always mosaic larger images. I can't get sharpness over the entire 640x480 chip in 6/10 seeing.
On a side note, large ccd pixels capture more light than small pixels do. So you can run at higher frame rates or use longer focal lengths too. Also you get a wider field of view too - which is a mixed blessing.
All things considered, I would recommend the DMK21AF04 mono camera - I think it is a good marriage of cost and quality. (The DFK is a color camera, I think).
Just for clarity, the second letter of the Imaging Source Camera model name indicates if the camera is color or monochrome. So a DMK (M) is a monochrome camera and anything else (i.e DBK, DFK etc.) is color.
I bought a very nice manual filter wheel from a maker in Italy for about 300.00. I have also heard good things about the ATIK manual wheel - I think it is 100. less expensive. There is a lot of versatility to the mono cameras - a little more work too, but if you get hooked, I think you will find it a good trade off.
Also check out Apogee Inc
whom have a manual 4 filter wheel for about $90.00 USD. I have one of their 3 filter wheels here.
The main benefit with a monochrome camera is that there is no color processing needed to create an image. So you wind up with better (about 2 times) resolution per pixel because for color imaging, one has to use adjacent R G B color pixels from the Bayer Color Filter Array and dither them to create the RGB image. This is the primary reason a color camera makes a very poor choice for doing precision estimates of absolute magnitudes of stars.
HTH..
Milton J. Aupperle
President
ASC - Aupperle Services and Contracting
Mac Software (Drivers, Components and Application) Specialist
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